Electronic devices often need to generate multiple power regimes while only being powered by a single source. For example, a laptop computer may only have a single battery but may need to produce power regimes with different supply voltages for the various components on the laptop. Furthermore, regardless of the need for multiple power regimes, electronic devices often need to condition the power that is delivered to them from an external source. Returning to the example of a laptop, the laptop processor contains sensitive electronics and exhibits a widely varying power demand based on how hard the processor is working. Simply plugging in a DC version of the mains voltage source is not an option because the processor will not be shielded from dips or surges in the power supply and the power supply will likewise not be able to keep pace with the rapid transitions in the power drawn by the processor. The aforementioned requirements are addressed by power converters.
FIG. 1 provides a block diagram of an example power converter 100 regulating power applied to a load 101. In this example, the input is a voltage VIN provided on an input node of the power converter and the output is a voltage VOUT provided on an output node of the power converter. Alternative power converters may regulate an output current while allowing a voltage at the output node of the converter to vary. Power converter 100 regulates the load by altering the amount of power transferred through switching circuit 102 and output filter 103 using a control loop.
Switched mode converters are a specific class of power converters that utilize a control loop, switching circuit, and an output filter to control the transfer of power from the input regime to the output regime. In the illustrated example, switching circuit 102 is coupled to the input node, and serves to couple the input side of the power converter to the output side of the power converter. As illustrated, the control loop of power converter 100 includes a feedback path 104 that provides a control signal to switching circuit 102 that is based on a measurement taken from the output side of power converter 100. The feedback path includes signal conditioning and processing circuitry 105 and a driver circuit 106 for providing control signals to the power devices in switching circuit 102. For example, the driver circuit 106 could be a gate driver circuit for driving the gates of power transistors in switching circuit 102. The specific switching circuit illustrated by FIG. 1, in which the gates of two series-connected FETs are independently driven, is referred to as a totem pole or half-bridge switching circuit.